Conventionally, there has been heretofore known a twin-clutch automatic transmission in which multiple gear positions are divided into two gear position groups (odd gear position group and even gear position group), and which is equipped with a first clutch mechanism for selecting a gear position in one gear position group and a second clutch mechanism for selecting a gear position in the other gear position group (e.g., see JP 2009-97648 A). The twin-clutch automatic transmission of this kind is configured such that the other clutch mechanism is put into a disengaged state, while selecting the gear position in the gear position group corresponding to the one clutch mechanism, with the other clutch mechanism engaging. At this time, a gear drive system associated with the gear position corresponding to the other clutch mechanism is in a neutral condition where power is not transmitted. The twin-clutch mechanism is arranged to allow power transmission, through such an operation, with the prescribed gear position selected. The twin-clutch automatic transmission is configured to couple a first input shaft and an engine output shaft together by engaging the first clutch mechanism. Like this, twin-clutch automatic transmission is configured to couple the second input shaft and the engine output shaft together by engaging the second clutch mechanism. The first input shaft or the second input shaft is arranged to transmit a rotation via each driven gear to the output shaft of the twin-clutch automatic transmission.
An Engine Control Unit (ECU) is connected to an engine to be coupled with the twin-clutch automatic transmission of this sort. Moreover, a Transmission Control Unit (TCU) is also connected to the twin-clutch automatic transmission. The ECU is configured to receive a signal indicative of rotating speed information from an engine speed sensor which detects a engine speed, and a signal indicative of accelerator opening information and brake switch information, etc. By doing so, various decisions are done for engine control. The TCU is configured to receive signals from a first input shaft rotational sensor, a second input shaft rotational sensor, an output shaft rotational sensor, and a shift lever switch. Hereupon, the first input shaft rotational sensor is for detecting a rotating speed of the first input shaft, the second input shaft rotational sensor is for detecting a rotating speed of the second input shaft, and the output shaft rotational sensor is for detecting a rotating speed of an output shaft of the twin-clutch automatic transmission, respectively. The TCU is configured to do various decisions for outputting a control signal to a shift-clutch actuator. Between the ECU and the TCU, communication is made via bidirectional Controller Area Network (CAN) communication.
As a representative of clutch torque capacity regulation executed in a control apparatus for the twin-clutch automatic transmission on starting a vehicle, an approach is well known to control slip quantity of an engine speed and a clutch speed. In this approach, the torque capacity of the clutch is regulated such that a target engine speed is determined from at least accelerator opening to achieve the target engine rotation. Usually, it is the custom to do clutch torque capacity regulation by synthesizing feed-forward control in response to torque to be input and feedback control in response to a deviation between the target engine speed and an actual engine speed. However, this approach is problematic that a too much feed-forward controlled variable can cause an engine stall due to factors, including engine torque accuracy, feasibility of torque clutch capacity, variations in response lag, and environmental changes such as temperature. Under these circumstances, it is often the case that the feedback control is sometimes regarded as more important than the others.
Prior Art Document
Patent Document